FG 36-E
Revised August 2005
Tall Fescue Grown for Seed
(Western Oregon)
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J.M. Hart, M.E. Mellbye, D.A. Horneck, G.A. Gingrich, W.C. Young III, and T.B. Silberstein
Tall fescue is grown for turf or forage seed on a broad
range of soils in western Oregon. Typical seed yield
is 1,200 to 2,000 lb/acre. Higher yields do not require
additional nutrients beyond amounts recommended in this
guide. These recommendations, especially for nitrogen, are
adequate for production of more than 2,500 lb/acre seed on
sites where soil pH and drainage do not limit yield.
Research has demonstrated that plant growth regulators increase tall fescue seed yields. However, use of plant
growth regulators does not increase the need for nitrogen,
phosphorus, potassium, or sulfur fertilizer.
Appropriate management practices from seedbed preparation to harvest must be performed in a timely manner for
optimum seed yield. Low soil pH, poor drainage, insects,
diseases, and weeds all reduce seed yield. Increasing fertilizer rates when nutrients are in adequate supply will not
compensate for other limiting factors.
Soil testing is recommended to determine nutrient availability. Sample and analyze soil before planting to provide
a basis for lime, phosphorus, potassium, calcium, and
magnesium application. A single sample should represent
a single soil type, or the same management practices in a
field, and should not exceed 40 acres.
If a tall fescue field remains in production for more than
4 years, sample soil after the third year, especially if you
bale the straw. Local Oregon State University Extension
Service offices can provide additional information,
including the publications A List of Analytical Laboratories Serving Oregon, Monitoring Soil Nutrients Using a
Management Unit Approach, and Soil Test Interpretation
Guide. (See “For more information,” page 3.)
This guide recommends supplying nutrients with
topdress or band applications during the fall and late
winter/early spring. Foliar fertilizer applications during
heading may contribute to seed yield in some situations.
Research shows that foliar fertilizer applications increase
seed yield 100 to 200 lb/acre about 25 percent of the time.
Late-season foliar fertilization should be used only on a
trial basis and should not take the place of or reduce recommended spring nutrient inputs.
Nitrogen (N)
Nitrogen recommendations in this guide are in addition
to the nitrogen supplied by the soil. Soil typically supplies
50 to 100 lb N/acre annually, depending on soil type and
stand age. Soil nitrogen supply usually is highest after
tillage, about 100 lb N/acre for the first 2 years of a stand,
decreasing to about 50 lb N/acre in subsequent years.
Poorly drained soils with more than 5 percent organic
matter supply more nitrogen than well-drained soils with
lower organic matter. Use lower nitrogen rates for poorly
drained soils, as these soils have shown an erratic response
to higher rates.
New seeding
Apply 20 to 40 lb N/acre at seeding. If nitrogen is
banded at planting, at least 1 inch of soil should separate
the seed from the fertilizer so the fertilizer does not delay
crop emergence. If charcoal seeding is used, nitrogen may
be included in the charcoal solution.
Established stand
Post-harvest residue management does not alter nitrogen fertilizer need. Regardless of whether the straw is
removed, chopped back, propane burned, or open field
burned, tall fescue fields have a similar nitrogen requirement in typical 3- to 4-year rotations.
Fall application
TH
Fall nitrogen is necessary to increase the number of
reproductive tillers and is important for optimum seed
yield. In OSU on-farm field tests, fall nitrogen increased
seed yield by an average of 170 lb/acre compared to no fall
nitrogen. Apply 30 to 40 lb N/acre in early October. Fall
nitrogen rates higher than 40 lb N/acre did not increase
seed yield in field tests as long as adequate nitrogen was
applied in the spring.
1
John M. Hart, Extension soil scientist; Mark E. Mellbye, Extension faculty, Linn County; Donald A. Horneck, Extension faculty,
Morrow and Umatilla counties; Gale A. Gingrich, Extension faculty
emeritus; William C. Young III, Extension seed production specialist; and T.B. Silberstein, Extension agronomist, Marion County; all
of Oregon State University.
Post-harvest residue management strongly influences
potassium need. Straw contains 20 to 30 times more
potassium than seed. Potassium in grass straw, or ash from
burned straw, is immediately available to the next crop.
Straw removal eliminates this source of potassium and can
accelerate reduction in soil test potassium.
Spring application
Spring nitrogen application commonly increases seed
yield 300 to 900 lb/acre compared to no spring N application. Optimum tall fescue seed yield typically can be produced by applying 90 to 140 lb N/acre as soil drains and
spring growth starts, usually beginning in March. Lower
rates of nitrogen are suggested for the poorly drained and
higher organic matter soils of the Willamette Valley. Nitrogen rates below 90 lb N/acre produced top seed yields in
50 percent of the sites in on-farm research from 1998 to
2000. However, only 10 percent of the sites responded
with top seed yield when nitrogen application was above
135 lb N/acre.
Although not essential for optimum seed yield, a split
nitrogen application is recommended for uniformity and
ease of management, to accommodate crop uptake, and to
provide flexibility in avoiding unfavorable weather conditions. The final nitrogen application should occur before
mid-April.
Do not apply nitrogen to fields with standing water.
Nitrogen applied when soils are saturated and plants are
yellow will not promote growth.
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Table 2.—Potassium fertilizer application rates for tall fescue
based on a soil test using the ammonium acetate extractant for
determination of plant-available K.
Apply this amount of K2O
Established stand
If soil test* for K is New seeding
Bale Burn/chop
(ppm)
(lb/acre)
(lb/acre) (lb/acre)
0–100
101–150
151–200
over 200
Sulfur (S)
A spring sulfur application of 10 to 15 lb/acre is preferred, but sulfur also can be applied in the fall.
Compare the results of a soil test that uses the Bray
method for phosphorus to the values in Table 1 to determine the rate of P2O5 to apply for a new seeding or established stand.
When banding phosphorus at planting, at least 1 inch
of soil should separate the seed from fertilizer. For established fields, phosphorus can be applied at any time.
Micronutrients
Seed yield increases from micronutrient applications
generally are not expected in western Oregon. Although
soil test boron (B) levels normally are low (less than
0.2 ppm), seed yield increases from boron application have
been limited and inconsistent. Tissue and soil test boron
increase with a soil boron application. A single application
of 1 lb B/acre will increase tissue boron for several years.
Zinc (Zn) usually is adequate for grass seed production
when the DTPA soil test is above 0.6 ppm. If the soil test is
below 0.6 ppm, apply 1 to 5 lb Zn/acre on a trial basis.
Table 1.—Phosphorus fertilizer application rates for tall
fescue based on a soil test using the Bray extractant for
determination of plant-available P.
Apply this amount of P2O5
New seeding Established stand
(lb/acre)
(lb/acre)
0–15
16–25
over 25
40–60
30–40
0
150–200 100–150
75–150 50–100
0–75
0–50
0
0
* Ammonium acetate
Phosphorus (P)
If soil test* for P is
(ppm)
200–250
100–200
30–40
0
Lime
30–40
0
0
Stand establishment can be marginal or even fail if soil
pH is below 5.0. When soil pH is less than 5.5, lime is
recommended. Use Table 3 (page 3) to determine the lime
application rate based on the SMP buffer. Do not exceed
5 tons/acre in a single lime application even if the SMP
lime requirement is greater.
For best results, mechanically incorporate lime during
seedbed preparation. Topdressing lime is not as effective
as incorporation. Topdressing lime without incorporation raises soil pH in only the surface inch of soil and will
not produce changes in plant growth for at least 1 year
after application. Topdressed lime applications should not
exceed 1 to 2 tons/acre.
TH
*Bray P1
Potassium (K)
Compare the results of a soil test that uses the ammonium acetate extraction for potassium to the values in
Table 2 to determine the K2O rate. When banding potassium at planting, at least 1 inch of soil should separate the
seed from fertilizer. Do not exceed 30 to 40 lb K2O/acre
when banding potassium with seed at planting. A banded
application of N plus K should not exceed 90 lb/acre total
nutrients (not fertilizer material). For established fields,
potassium can be applied anytime.
2
Table 3.—SMP buffer lime requirement for tall fescue.
SMP buffer
6–5 **
5–4
4–3
3–2
2–1
0
0
8–7 **
7–6
6–4
4–3
3–2
2–1
1
OSU Extension publications
Many OSU Extension Service publications may be
viewed or downloaded from the Web. Visit the online
Publications and Videos catalog at http://extension.
oregonstate.edu
Copies of many of our publications and videos also
are available from OSU Extension and Experiment
Station Communications. For prices and ordering information, visit our online catalog or contact us by fax
(541-737-0817), e-mail (puborders@oregonstate.edu), or
phone (541-737-2513).
Fertilizer and Lime Materials Fertilizer Guide, FG 52-E
(revised 1990).
A List of Analytical Laboratories Serving Oregon, EC 628
(revised 2002).
Monitoring Soil Nutrients Using a Management Unit
Approach, PNW 570-E (October 2003).
Nitrogen Uptake and Utilization by Pacific Northwest
Crops, PNW 513 (1999).
Soil Test Interpretation Guide, EC 1478 (published 1996,
reprinted 1999).
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4.8–5.0
5.1–5.3
5.4–5.6
5.7–5.9
6.0–6.2
6.3–6.5
over 6.5
Amount of 100-score lime needed
to raise pH of surface 6 inches of soil
to the following pH*
5.6
6.0
(tons/acre)
(tons/acre)
For more information
*The combination of calcium carbonate equivalent, moisture, and
fineness determines lime score. Lime application rates are adjusted
for score. Rates in Table 3 are based on 100-score lime. Lime score
is legally required for all materials marketed as “liming materials” in
Oregon. For more information about lime score and liming materials, see FG 52-E, Fertilizer and Lime Materials Fertilizer Guide.
**The higher lime rate is required for the lower buffer test reading.
TH
Calcium (Ca) and magnesium (Mg) exist in the soil in
adequate quantities when soil pH is above 5.5. For acidic
soil with less than 0.5 meq/100 g soil or 60 ppm magnesium, apply 1 ton dolomite/acre. Dolomite and lime have
approximately the same capability to neutralize soil acidity and increase soil pH. An alternative to dolomite is to
broadcast 30 lb Mg/acre annually. Compare material cost
before choosing a magnesium source.
Use of most common nitrogen fertilizers increases
surface soil acidity and lime need. Urea or other ammoniacal nitrogen sources acidify soil approximately 0.1 pH
unit for each 100 lb N/acre. For example, if nitrogen is
applied at the rate of 140 lb/acre, the soil pH will decrease
by approximately 0.14 pH unit. If 140 lb N/acre is used for
3 years, soil pH will decline approximately 0.4 pH unit.
Thus, the use of nitrogen fertilizer beyond crop need has
a double cost. The first cost—the nitrogen fertilizer itself—
is not offset by increased seed yield or economic return.
Second, the additional nitrogen acidifies soil, which then
requires additional lime to raise the soil pH. Application
of 50 lb N/acre above crop need will require an additional
0.3 to 0.6 ton lime/acre in 3 years.
Other publications
Mellbye, M.E., G.A. Gingrich, N.W. Christensen,
J.M. Hart, and M. Qureshi. 1997. “Nutrient Uptake
by Tall Fescue Under Full Straw Load Management.” In: W.C. Young III (ed.), 1996 Seed Production Research at Oregon State University, USDA-ARS
Cooperating, Department of Crop and Soil Science
Ext/CrS 110 (April 1997).
Young, W.C. III, M.E. Mellbye, G.A. Gingrich,
T.B. Silberstein, T.G. Chastain, J.M. Hart, and
S.M. Griffith. 2003. “Defining Optimum Nitrogen Fertilization Practices for Grass Seed Production Systems
in the Willamette Valley.” In: W.C. Young III (ed.),
2002 Seed Production Research at Oregon State University, USDA-ARS Cooperating, Department of Crop
and Soil Science Ext/CrS 122 (May 2003).
Young, W.C. III, T.B. Silberstein, T.G. Chastain, and
C.J. Garbacik. 2003. “Fall Nitrogen on Tall Fescue.” In: W.C. Young III (ed.), 2002 Seed Production
Research at Oregon State University, USDA-ARS
Cooperating, Department of Crop and Soil Science
Ext/CrS 122 (May 2003).
Young, W.C. III, T.B. Silberstein, T.G. Chastain, and
C.J. Garbacik. 2004. “Fall Nitrogen on Tall Fescue.” In: W.C. Young III (ed.), 2003 Seed Production
Research at Oregon State University, USDA-ARS
Cooperating, Department of Crop and Soil Science
Ext/CrS 123 (March 2004).
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Revised August 2005.